The NASA rover team thinks the shiny object could be a piece of the rover, and are stopping to investigate, since if there's more rover debris in the sand, since it could seriously mess up the scooping mission if it got into the rover's machinery.

Planetary Society blogger Emily Lakdawalla thinks it could be a piece of the Kapton tape, which is used on many parts of the rover. She found a picture from the rover's chemcam that may be of the object in question. It looks like it could be a piece of rover tape, nestled in between all those pebbles.

Curiosity Chemcam image of what might be a piece of the rover's own shiny tape that's distracted the rover. NASA/JPL-Caltech

Before getting distracted, the rover did get some of the sandy Martian dirt picked up and shook it around to clean out her scooper. Here's a video NASA put together from images taken of the shaking in action:

UPDATE: NASA scientists confirmed Tuesday that the object is likely a bit of plastic from the rover itself. From the release:

The rover team's assessment is that the bright object is something from the rover, not Martian material. It appears to be a shred of plastic material, likely benign, but it has not been definitively identified. To proceed cautiously, the team is continuing the investigation for another day before deciding whether to resume processing of the sample in the scoop. Plans include imaging of surroundings with the Mastcam.